[Troy T.]

Hello,
I have been toying with the idea of building a new box for my truck i
have been looking at different specs and stuff and i was wondering what
the advantage or disadvantages is to having more or less air volume
inside the box? thank you for any replies

TroyT.

[KU40]

generally, higher volume will increase low end extension and sensitivity
(less power to reach full excursion), but too large of a box may lose
transient response because of the less control over the cone.

lower box volume is basically the opposite.

Most people go for something in-between.


--
KU40

[D.Kreft]

On Dec 26, 3:10 pm, "Troy T." wrote:

I have been toying with the idea of building a new box for my truck i
have been looking at different specs and stuff and i was wondering what
the advantage or disadvantages is to having more or less air volume
inside the box? thank you for any replies

KU40's advice is sound (no pun intended). But it's important that you
follow the manufacturer's recommendations for enclosure volumes and
types.

-dan

[Troy T.]

thank you both for the advice, i was looking up the specs for my sub
and there are specs for 3 different types of sealed boxes and one of
them is Low Qtc sealed enclosure, and i was wondering what exactly that
is and how does it compare to normal boxes or a SPL box because those
are the other types of boxs they give specs for.
here is the link to the specs the box volume is towards the bottom:
http://www.orioncaraudio.com/subwoof...b_p_series.asp

thank you again

TroyT.

[D.Kreft]

On Dec 27, 10:29 am, "Troy T." wrote:

thank you both for the advice, i was looking up the specs for my sub
and there are specs for 3 different types of sealed boxes and one of
them is Low Qtc sealed enclosure, and i was wondering what exactly that
is and how does it compare to normal boxes or a SPL box because those
are the other types of boxs they give specs for.
here is the link to the specs the box volume is towards the bottom:http://www.orioncaraudio.com/subwoof...b_p_series.asp

Okay, this makes your question seem much more sane. :-)

The problem with those "specs" is that they really don't tell you much.
For example, what they consider "low" Qtc.

Strictly speaking, a system with a Qtc of 0.707 is considered
"critically damped" (google for it if you're curious). Anything below
this magical value is considering "low Q" and anything over it is "high
Q". A common newbie mistake is to look at any given spec outside of the
context of the other specs related to it. In this situation, it would
be a mistake to pick an alignment based upon Q values without also
considering the F3 (the -3dB point)....that is, if they gave you the
information you need to make such an informed decision. :-) If your
Qtc is "too low" (according to your taste and usage), then your
subwoofer will sound really lifeless and "dry" to you; conversely, if
it is "too high", it'll seem boomy and resonant. Some people prefer one
over the other, so mileage always varies.

As a general rule of thumb for sealed boxesx, for the typical listener,
a good starting place is a Qtc between 0.8 - 1.2 with a -3dB point
somewhere in the general range of 35 - 45 Hz...and it can be tweaked
from there. What most people are looking for is a fairly decent LF
extension with a 1-2dB "bump" in response above your -3dB point--but
how much of a bump is going to be tolerable depends (again) upon the
Qtc and your preferences.

Your best bet is to have someone experienced with this driver assist
you in picking an enclosure size based upon your personal preferences
and your other system components.

See http://mobile.jlaudio.com/support_pages.php?page_id=149 for a
little more on sealed boxen.

I hope this helps.

-dan

[MaGurk]

What the manufacturer suggests, should only be a guidline or starting
point. They are dead wrong sometimes. Going strictly with what they
suggest is like only buying prefab boxes.


--
MaGurk

[D.Kreft]

On Dec 27, 1:15 pm, MaGurk
wrote:

What the manufacturer suggests, should only be a guidline or starting
point. They are dead wrong sometimes.
Going strictly with what they suggest is like only buying prefab boxes.

This seems like a bit of an overstatement and in general is not true.
Nobody knows the product more than the people who make the product. It
may be crappy product to begin with, but they'll still know more about
their crap than anyone else does because they (presumably) spent some
time researching, engineering and testing it. So, going with what they
suggest (particularly if you get it direct from someone in Technical
Support) is not necessarily a bad thing to do--it can actually be the
*best* thing to do. But as with anything else in life, you have to
consider the source. I don't think I'd have a problem following any
*reputable* manufacturer's recommendations.

And I have to take exception to your unqualified maligning of "prefab
boxes". If you're talking about someone just slapping a box together
and routing-out some big holes on it and saying "this box is for
10-inch subwoofers", then yes, I would agree with you that this is a
mistake. However, in the context of your post (and of the thread), I
can only assume you are talking about the boxes that the manufacturer
makes specific for its own product, and in that case I cannot disagree
more with you...again, assuming a reputable manufacturer. The one
company with which I am most familiar is JL Audio, and I can personally
attest (having once been on their payroll) that they do *not* slap
things together and that even their "bottom of the line" pre-fabricated
enclosures are very high quality and will yield great results for the
vast number of "typical customers". These pre-made enclosures will
likely not satisfy the "golden-eared tweak" nor the "bass monkey", but
those customers are at two different extremes of the distrubution of
customers.

To sum it all up: not all manufacturers are stupid, nor are all
"pre-fab" boxes bad.

-dan

[KU40]

I agree with D. Kreft, but I think I have one thing to add, and that is
to understand the marketing of the company and how it relates to their
box suggestions. I've seen some companies (I think Kicker may have
been one at one time) that markets their subs as SPL machines, so they
recommend ported boxes with high tunes (like 40+ hz). You just have to
realize they are marketing towards basshead teens who like to impress
their friends, who will in turn buy the same thing. Most don't fully
understand sound quality or want a flat frequency response across the
spectrum.

At the same time, some manufacturers may recommend a higher tune than
you'd think, but it's for a reason. For example, RE recommends their
new XXXs to be put in a box tuned to 36 hz. To me this seems high at
first glance, but they built that sub with massive xmax that more than
takes care of the lowend, even under tune. With a lower tune the lowend
will just be overbearing.

There are other companies that go for the super flat response as low as
possible, so they may recommend something around 26-28 hz for a tune.

So when I think of making a box for a sub, I would start with the
manufacturer's recommendation, maybe adjust up or down depending on the
reputation or marketing style of the company, and also look at the specs
to see if the sub is strong or weak in a certain area that the
manufacturer may be compensating for with their suggestion.


--
KU40

[MaGurk]

You guys rock, I'm so glad I didn't get totally flamed for my view on
the subject. I just would rather people knew more about enclosures and
didn't consider the manufacturer's recommendations the only route to
take. JL Audio does indeed know their stuff. Some brands though are
just dead wrong in what they suggest. I've never worked with Orion, so
I am going to leave it at that. Thanks for the grown up responses
though... those seem to be few and far between on the forums anymore.


--
MaGurk

[Troy T.]

Thank you all for your responce.I am kinda curious as to what you guys
suggest.I have noticed that you guys dont like the "boomy" and do like
the nice clean bass inorder to achieve good SQ,which is also what i am
going for with my system. so i what you guys would do. thank you for
your help

TroyT.

[KU40]

I just clicked that link you gave to the orion site. the 40 hz
recommendation for the 12 is what I was talking about. The 50 hz
recommendation for the 10" is just ridiculous.

If you're going sealed, I'd do 1 cubic foot.


--
KU40